Use GError in FLAC tagging code

Avoid several uses of Log_Print().
Use GError in APE tagging code

Avoid a use of Log_Print().
Use GError in ID3 tagging code

Avoid several uses of Log_Print(), and convert some more into warnings
or debugging messages.
Use GError in MP4 tagging code

Avoid several uses of Log_Print().
Use GError in Ogg header code

Avoid a few Log_Print() calls.
Use GError in WavPack tagging code
Report successful writing in UI, not in tag code

Remove several Log_Print() calls in the tagging code, and instead report
the successful writing of a tag in the UI.
Unify logging code for tag reading